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Function __extent_writepage_io() is designed to find all dirty ranges of a page, and add the dirty ranges to the bio_ctrl for submission. It requires all the dirtied ranges to be covered by an ordered extent. It gets called in two locations, but one call site is not subpage aware: - __extent_writepage() It gets called when writepage_delalloc() returned 0, which means writepage_delalloc() has handled delalloc for all subpage sectors inside the page. So this call site is OK. - extent_write_locked_range() This call site is utilized by zoned support, and in this case, we may only run delalloc range for a subset of the page, like this: (64K page size) 0 16K 32K 48K 64K |/////| |///////| | In the above case, if extent_write_locked_range() is only triggered for range [0, 16K), __extent_writepage_io() would still try to submit the dirty range of [32K, 48K), then it would not find any ordered extent for it and triggers various ASSERT()s. Fix this problem by: - Introducing @start and @len parameters to specify the range For the first call site, we just pass the whole page, and the behavior is not touched, since run_delalloc_range() for the page should have created all ordered extents for the page. For the second call site, we avoid touching anything beyond the range, thus avoiding the dirty range which is not yet covered by any delalloc range. - Making btrfs_folio_assert_not_dirty() subpage aware The only caller is inside __extent_writepage_io(), and since that caller now accepts a subpage range, we should also check the subpage range other than the whole page. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.